Ignition apparatus for internal-combustion engines.



E. A. WATSON.

iGNlTlON APPARAILLS FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED FEB. 19, 1918.

1 ,302,107. I Patented Apr. 29, 1919.

2 SHEETS-SHEET 1.

Fig.1

E. A. WATSON.

IGNITION APPARATUS FOR'INTERNAL COMBUSTION ENGINES.

APPLICATION FILED FEB. 19. I918,

1 ,302, 1 O7, Patented Apr. 29, 191.9.

2 $HEETSSHEET 2.

INVENTOR ATTORNEY STATES PATENT OFFICE.

ERNEST ANSLEY WATSON, OF WEST ORCHARD, COVENTRY, ENGLAND, ASSIGNOR TO THE M-L MAGNETO SYNDICATE LIMITED, 0] WEST ORCHARD, COVENTRY, ENGLAND.

IGNITION APPARATUS FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Apr. 29, 1919.

Application filed February 19, 1918. Serial No. 218,119.

To all whom it may concern:

Be it known that I, ERNEST ANsLnY WAT- SON, M. Sc., en ineer, residing at Victoria Works, West rchard, Coventry, in the county of Warwick, England, subject of the King of Great Britain and Ireland, have invented certain new and useful Improvements Relating to Ignition Apparatus for Intercombustion engines, namely, magnetos which generate their own current and induction coils which derive their current from a battery or dynamo. "A characteristic of the magneto is that the energy content of the spark increases with the speed of operation of the machine, while" the corresponding characteristic of. the induction coil is that the energy content of the spark diminishes with the speed of operation. Generally with an induction coil there is a limit of speed beyond which no'sparks can be obtained and at or justbelow that speed the sparking is irregular. .The explanation of this difference is to be found in the fact that in the magneto the magnetic flux is produced in the core carrying the primary and secondary windings while the primary circuit is 0 en and conseuently the flux reaches its ll value quic y and without any retarding eflect due to an induced current in the primary. In the induction coil the primary must necessarily be closed before any mag-- netism can be set up therein and in consequence the rate of growth of the flux follows that of the current and depends upon the time constant of the circuit. The interval during which the circuit remains closed di minishes as the speed of rotation of the in- .terrupter increases and as a result the magnetism available for use in producing the high tension spark diminishes also.

For high speed engines and particularly engines having a large number of cylinders there is a limit-to the usefulness of an ordinary induction coil when as is necessarily the case in practice the size of the same is restricted.

The object of the present invention is to overcome the above described limitation to the induction coil type of ignition apparatus number of salient is connected with the armature core,

4 axis of the armature.

poles of one disk f and secondary winding (or what is commonly known as battery ignition apparatus which may derive its current from either a battery or a dynamo), and for this purpose the invention comprises the employment of means whereby magnetism is separately supplied to the core of the induction coil during the interval when the primary circuit is open. In particular the invention comprises the employment of a stationary primary and secondary winding herein termed the induction coil in conjunc tion with a magnetic system which consists in part of a rotary armature carrying an exciting winding, the armature being shaped to periodically open and close the magnetic circuit of the induction coil and supply the same with magnetism during the open circuit intervals of the primary.

Referring to the two accompanying sheets of explanatory drawings I Figure 1 is a longitudinal section of an ignition apparatus constructed in accordance with this invention and-adapted to provide twelve sparks per revolution.

Fig. 2 is an end view in which the four quadrants of the circular part shows diiierent portions of the mechanism. I

Fig. 3 is a cross section through the electro-magnetic system. I

In applying the invention to battery ignition apparatus for a twelve cylinder engine, a circular rotary armature core a of disk form is provided on each side with a pole pieces I), each pole piece being bent t right angles so that it consists of a part which is radial to and and a is parallel with the The peripheral parts lie across the armature and inclose an annular' winding 0 on the annature core. The

peripheral part which poles of the opposite disk, so that successive poles are of opposite polarity. 'In con unction with the said peripheral portions of the poles are a pair of laminated limbs d elftending from'the opposite ends of a larnlnated core 6 carrying the primary windmg of the induction coil. The disposition of the armature pole pieces and the magnetic circuit of the 1nduction coil is such that during the rotation of the armature the pole pieces intermittently' open and close the magnetic c1!- lie alternately with the 'cu-it through the induction coil and alternately magnetize the same 1n opposite directions.

Any suitable means such as a slip ring h 1s provided to conduct current to the armature winding, and a mechanical interrupter" of any convenient form (such as a cam 11 and contact lever j) is employed for opening and closing the circuit of the primary winding f; It will be understood that the armature winding and primary winding form separate circuits to which current is conducted from a supply battery or direct current generator. The usual condenser r. is

arranged in conjunction with the interrupter. l/Vhen the primary circuit is open magnetism is supplied to the core of the induction coil by the armature.- On closing the said circuit. the magnetism is augmented by that induced by the current which flows therein to the instant of breaking. At low speeds of rotation the magnetism due to the current in the primary may exceed that due tothe armature. As the speed increases the former diminishes, but the latter remains constant and is made suflicient 'to provide sparks of the required intensity at any speed. Thus at low speeds the working of the apparatus is comparable to that of an ord1nary induction coil, and at high speeds 1s comparable to that of an ordinary mag-- neto. 1

In a convenient construction the mechanism is mounted in a hollow easel carrying the armature and adapted for direct end- W se attachment to the engine crank case in ahnement with any convenient shaft such as the crank-shaft to which the armature spindle m is coupled. On the outer end of the armature shaft is arranged the interrupter above mentioned and the distribute-r. In thedrawings the latter is shown of the jump spark type consisting of a rotary radial arm n receiving high tension current from a terminal 0 through a slip ring 1), and terminals g which are connected to the engine plugs and convey current from the radial arm. The induction coil is carried in a separate detachable housing 1" surmounting the case of the armature.

The invention is not limited to any particular constructional or mechanical details 'duction 0011, a circuit breaker, and means independent of the circuit breaker. whereby magnetism is separately supplied to the induction c011 during the open circuit period of the coil, substantially as described.

.as described.

2. In ignition apparatus for internal coin bustion engines, the combination comprising stationary primary and secondary windings, a core carrying the same, said windings and core forming an induction vcoil, a circuit breaker, a rotary magnetic system adapted to cooperate with the magnetic system of the coil and supply magnetism to the same during the open-circuit period of the primary winding of the induction coil, substantially 3. In ignition apparatus for internal combustion engines, the combination comprising primary and secondary windings and a core forming a stationary induction coil, coreextensions, a circuit breaker, a rotary armature, salient poles on the armature co-actin'g with the core extensions and. an exciting winding on the armature, the poles being arranged to intermittently supply magnetism to the core during the opencircuit period of the primary winding, substantially as described.

4:. In ignition apparatus for internal'combustion engines, the combination comprising primary and secondary windings and a core forming a stationary induction coil, .extensions on the ends of the core, a circuit breaker, a rotary spindle, a pairof iron disks formed with peripheral pole pieces on the spindle, the pole pieces of one disk alternating with those of the other disk and the two sets of pole pieces being arranged to intermittently supply magnetism to the core during the open circuit period of the primary winding, and an exciting winding ,between the disks,substantially as described.

5. In ignition apparatus for internal combustion engines, the combination comprising.

stationary primary and secondary windings and core forming a stationary inductlon coil,

a circuit breaker, core extensions, arotary exciting armature provided with pole pieces co-acting with the core extensions and anterm'ittently supplying magnetism .to the core during the open circuit period of the primary'winding, a slip ring on the armature for conveying armature exciting current, a spindle carrying the armature, a high tension distributer'arm and an interrupter cam on said spindle, and an interrupter lever adjacent to the cam for controlling the current to the primary winding, substantially as described.

6. In ignition apparatus for internal combustion engines, the combination comprising primary and secondary windings, a core carrying said windings, parallel extensions on said core, a rotary exciting armature having its axis at right angles to the plane of the core and extensions; pole pieces on said armature'for intermittently supplying magnetism to the core during the open circuit period of the primary winding, aspindle carrying the armature, a high tension dis.-

tributer arm and an interrupter cam on the tachable cover on one side of the body inspindle, an interrupter lever adjacent to the closing the primary and secondary Winding, cam for controlling the primary current, a substantially as described. 10 slip ring on the armature carrying the arma- I In testimony whereof I have signed my ture exciting current, a cylindrical body carname to this specification.

rying the armature and its associated'parts, a

distributeron one end of the body and a de- ERNEST ANSLEY WATSON. 

